As electronic devices, such as cell phones, laptops, tablets and electronic readers become more popular, and as users take their devices with them into public places, the need to secure the devices against unauthorized use becomes more acute. Typically, devices are secured through some sort of device lock that requires the user to remember and enter via the device's user interface a secret security code, such as a password, personal identification number or passcode that functions as a key to unlock the device. This allows the user to be authenticated as an authorized user of the device before it is unlocked.
The reliability and usefulness of the device lock depends on a number of factors, such as the strength of the secret security code and the user's ability to remember it. If the device lock is too cumbersome or the secret security code is difficult to remember, users might not bother to lock their device. Conversely, if the device lock is too easy or the secret security code is easy to remember, the device lock might be easily compromised. Either way, the device is vulnerable to unauthorized use. Moreover, unlocking the device in a public space renders the secret security code vulnerable to observation attacks.
Other features of the present invention will be apparent from the accompanying drawings and from the detailed description that follows.